Fluid borne noise generated within a pressurized hydraulic system which uses a pump such as an automotive power steering system, can cause undesired noise and vibration. The oscillating pressure ripples generated by the hydraulic pump are carried within the hydraulic hose and tubing and cause other components to vibrate and emit noise. The use of a tuning tube or cable mounted within a fluid conveyance hose to attenuate these pressure oscillations is known in the art with a description of such of system in U.S. Pat. No. 3,323,305 entitled Attenuation Device and issued to G. Klees on Jun. 6, 1967. The fluid noise reduction structure of the prior art comprises a flexible plastic tube, called a tuning tube, that is attached to a hydraulic connector and then placed inside a section of hydraulic hose. The hose is usually permanently attached to the connector by crimping a socket formed on the fitting. The tuning tube can have holes formed along its length to increase the level of attenuation of the pressure pulses and hence, the level of generated noise. The material used for the tuning tube (or tuning cable) can be plastic such as PTFE (Teflon) or flexible metal such as a corrugated tube, or a wound or woven tube out of a material such as fiberglass and other similar materials such as rubber or synthetic rubber.
The tuning tube can be made of some type of plastic material such as nylon or PTFE (Teflon) or a spirally wound metal wall tube with a discontinuous wall construction that results in a distributed leakage along the length of the tuning tube can be used. It is known to use a connector that is both connected to the hydraulic hose and is connected to the tuning tube. If the tuning tube is made of a plastic tube material, the tube is commonly slipped over a relatively short barbed end of a hose nipple extending from the connector. The hose is attached to the fitting using a crimped socket that is mounted on the connector and overlies the nipple.
The length or other geometry of the tuning tube must be specifically selected to provide the highest level of attenuation depending on the frequencies generated by the pump and the natural vibration frequencies of the various components. Sometimes this can be empirically determined but even then, trial and error is most often used to determine the correct length of the tuning tube along with the location and size of any holes or other apertures along its length. Using the prior art system, the hose assembly is discarded every time the tuning tube is changed out which is time consuming and expensive. Thus, it would be desirable to have a development system that would permit the tuning tube to be easily changed without building a whole new hose assembly.